This application is based on and claims priority to Japanese Patent Application No. 2001-220120, filed on Jul. 19, 2001, and Japanese Patent Application No. 2001-252983, filed on Aug. 23, 2001, which are expressly incorporated by reference herein.
1. Field of the Invention
The present invention relates generally to an inverter type generator using a compact, light weight alternator configuration, and more particularly relates to an inverter type generator that includes two generating bodies wherein a first generating body provides an AC output voltage and a lower power output during a low engine speed range and a second generating body provides an AC output voltage and a higher power output during a high engine speed range.
2. Brief Description of Related Art
Conventionally, engine-driven generators are designed to be able to deliver a maximum possible power rating even if such power is not used or is only used for a temporary amount of time. As a result, typical engine-driven generators incorporate high-power engines to operate high-capacity generating bodies, making the overall design large, uneconomical, and heavy.
Typically, such engine-driven generator designs operate a generating body at a high speed so that the generating body delivers its rated power output at all times, even though the rated power is not needed for most of the time. Such operation causes the engine to run at an unnecessarily high speed, causing unwanted noise, fuel consumption, increased exhaust emissions, and high operating temperatures.
Conventional engine-driven generator designs that provide occasional high output power are heavy, loud, and too large. Because of noise, high temperature and high emissions, such conventional high-power generator designs are not operator friendly. Therefore, there is a need for an operator friendly, lightweight, quiet, environmentally friendly engine-driven generator design that is able to deliver adequate power when required.
Compact, lightweight, quiet, economical, and environmentally friendly engine-driven generators promote functionality, savings, and successful operation. Such improved designs however pose a challenge of providing adequate power when needed.
One aspect of a preferred embodiment of the present invention is a compact, lightweight engine-driven generator that incorporates a small engine. A first generator provides a lower output power at a lower engine speed range, and a second generator provides a higher output power at a higher engine speed range. The reduced engine size in combination with the two generators causes less heat to be generated and results in fuel savings when generating the lower output power, while being able to produce higher output power when required.
Another aspect of a preferred embodiment of the present invention is the use of an economy switch to allow the operating engine to run at a decreased speed when a high load is not present to thereby produce less noise, provide improved fuel economy, and produce lower exhaust emissions.